A lot of factors can affect the whole customer journey from one airport to another. One example would be airport delays.
We need to come up with a solution that takes into account the airport delays as well when finding the connections between airports.
https://app.swaggerhub.com/apis/FAA/ASWS/1.1.0#/FAA%20Airport%20Status%20Service/getDelays looks like a useful API to look at.
For a given day, on a higher level, after querying the flights from DB, we need to query the above API to get the delays between airports and add the delay-time to returned results.
But this approach does not guarantee the cumulative lowest travel time if we label the airport delays as "travel time" as well.
The business prospect of this use-case is open for discussion.